Telecommunication system

ABSTRACT

A telecommunication system for enabling a subscriber to calling features available by a central office to have access to such calling features when such subscriber is accessing the central office through either a line connected to the central office or an Internet, Intranet, Extranet (i.e., IP) network which uses the TCP/IP network protocol. The method includes the steps of: processing signals received by the central office from the subscriber through either the IP network or the line connected to the central office to determine whether the subscriber is placing a call to the central office through either the line to the central or through the IP network; and making such calling features available to the subscriber independent of whether the subscriber is connected to the central office through the line to the central office or through the IP network. With such a system, calling feature provided at a central office are available to a subscriber to such calling features anywhere ion the world via the IP network.

BACKGROUND OF THE INVENTION

This invention relates generally to telecommunication systems and moreparticularly to telecommunication systems adapted for used withInternet, Intranet, Extranet TCP/IP network protocol.

As is known in the art, Internet, Intranet, Extranet networks (referredto herein as IP networks) have supplemented public service telephonenetworks (PSTNs) in providing telephony services. For example, clientsoftware is available for enabling an Internet subscriber to place callsto a called party through the Internet. Typically, the calling partyaccesses the Internet via an Internet Service Provider (ISP) througheither a modem or a local area network (LAN) router. Data is transmittedfrom the calling party's ISP through the Internet using an Internetprotocol, typically the Transmission Control Protocol (TCP) and theInternet Protocol (IP) commonly referred to collectively as TCP/IP. ThisTCP/IP protocol is also used for Intranets/Extranets serving a specificclosed group of subscribers/users. Thus, the term IP network will beused to include any network using the TCP/IP network protocol. Therouting of information through an IP network is based on TCP/IPaddressing. A TCP/IP address is 32 bits long and is commonly expressedas four decimal numbers ranging from 0 to 256, with each numberseparated by a dot.

As is also known in the art, when accessing the ISP with a modem, theISP makes available a modem in a modem pool in what is sometimesreferred to as a “point-to-point” protocol. When accessing the ISP witha direct leased line, as from a LAN or cable company (CATV), datapackets transfer between the LAN or cable and the IP network directly asIP packets of information. The routing through the IP network is, asnoted above, using the TCP/IP network protocol with each point on the IPnetwork having a TCP/IP address. A router server is coupled to the IPnetwork to convert between an E.164 telephone number (i.e., using acentral office addressing protocol) and TCP/IP address (i.e., the IPTCP/IP network addressing protocol). Thus, for example, if a cable-basedIP user wishes to call a called party on the PSTN network, the callingparty dials the called party's E.164 directory number, the router serverconverts the dialed number to an TCP/IP number, the call is routedthrough the cable-based IP network to the TCP/IP address of an ISPgateway which then converts the TCP/IP address to the called party'sE.164 directory telephone number and directs the call through thecentral office on one of the lines (i.e., a trunk line) into the centraloffice.

As is also known in the art, a variety of services, or features, areavailable to subscribers of the PSTNs. For residential PSTN subscribers,these features include: Plain Old Telephone Service (POTS); customcalling features (such as, call waiting, call forwarding, three-waycalling, and speed calling, for example); advanced calling features(such as, called ID); Advanced Services for Display-Based Telephone Sets(ADSI); Digital Voice and Data on One Line (ISDN); Voice-ActivatedServices; Operator Services; and Voice Mail. For business PSTNsubscribers, these feature include: ISDN Line-Level Interface (BRI);ISDN High-Bandwidth Trunk Interface (PRI); Centrex Business TelephoneGroups; Automatic Call Distribution (ACD); Frame Relay DataTransmission; Videoconferencing; and Dialable WidebandServices/Bandwidth on Demand. A list of the features subscribed to arestored in a “features” database at the central office connected to thePSTN subscriber (i.e., the subscriber's central office, end office, orlocal switch). Thus, when a calling party goes “off-hook”, the centraloffice returns a dial-tone and then the calling party enters a calledparty's digits. A processor at the central office addresses the“features” database (and an administration database, for billing, etc.)using the calling party's telephone number, known as the calling party'sE.164. The central office processor reads the called digits and providesswitching signals to a central office switching network to route thecall to the called party with the calling party having available thesubscribed features stored in the “features” database. It is noted thatthe central office communicates internally and with other centraloffices in the PSTN with protocols (i.e., protocols adapted for use withanalog (POTS), ISDN, and PBX, for example) which are different from theTCP/IP network protocol.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method is provided forenabling a subscriber to calling features available by a central officeto have access to such calling features when such subscriber isaccessing the central office through either a line connected to thecentral office or an IP network. The method includes the steps of:processing signals received by the central office from the subscriberthrough either the IP network or the line connected to the centraloffice to determine whether the subscriber is placing a call to thecentral office through either the line to the central or through the IPnetwork; and making such calling features available to the subscriberindependent of whether the subscriber is connected to the central officethrough the line to the central office or through the IP network.

With such an arrangement, calling feature provided at a central officeare available to a subscriber to such calling features anywhere in theworld via an IP network.

In accordance with another feature of the invention, the central officeincludes a database for storing a relationship between each one of thesubscribers served by the central office and calling features subscribedto such one of the served subscribers. A processor in the central officedetects when a calling one of the subscribers served by the centraloffice is accessing the central office from either the subscriber lineunit or an IP network interface. The processor addresses the databaseusing the central office protocol and provides the calling subscriberwith the subscribed calling features when routed to a called party.

In accordance with still another feature of the invention, the centraloffice includes an IP network interface for converting between a centraloffice protocol and an IP protocol. A processor at the central office iscoupled to the IP network through the IP network interface. A switchingnetwork in the central office has ports fed by a subscriber line unit,trunk units, and the IP network interface. The switching network routescalls between the ports selectively in accordance with switching signalsprovided by the processor using the central office protocol with thecalling party having available calling features subscribed to by thecalling subscriber.

In accordance with another feature of the invention, a telecommunicationsystem adapted for use with an IP network is provided. The systemincludes a public service telephone network comprising a plurality ofconnected central offices each one being connected to a plurality ofsubscribers serviced by the central office. At least one of the centraloffices comprises a processor coupled to: a subscribe line unitservicing the subscribers served by the central office; trunk unitscoupled to other ones of the central offices; and an IP networkinterface. The IP network interface converts between a central officeprotocol and an IP protocol. The processor is coupled to the IP networkthrough the IP network interface. A switching network is provided havingports fed by the subscriber line unit, the trunk units, and the IPnetwork interface. The switching network routes calls between the portsselectively in accordance with switching signals provided by theprocessor using the central office protocol. A database is provided forstoring a relationship between each one of the subscribers served by thecentral office and features subscribed to by such one of the servedsubscribers. The processor detects when a calling one of the subscribersserved by the central office is accessing the central office from eitherthe subscriber line unit or the IP network interface and addresses thedatabase with the central office protocol to provide such callingsubscriber with calling subscribed features when the calling subscriberis routed to a called party through the switching network.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference is made to thefollowing description of an exemplary embodiment thereof, and to theaccompanying drawings, wherein:

FIG. 1 is a block diagram of a telecommunication system according to theinvention;

FIG. 2 is a flow diagram showing steps used by the telecommunicationsystem of FIG. 1 in enabling a subscriber to calling features availableby a central office of the system to have access to such callingfeatures when such subscriber is accessing the central office througheither a line connected to the central office or an IP network;

FIG. 3 is a block diagram of a telecommunication system according to theinvention wherein a cable-based IP network is provided;

FIG. 4 is a flow diagram showing steps used by the telecommunicationsystem of FIG. 3 in enabling a subscriber to calling features availableby a cable company's central office of the system to have access to suchcalling features when such subscriber is accessing the central officethrough a cable based IP network;

FIG. 5 is a block diagram of a telecommunication system according to analternative embodiment of the invention; and

FIG. 6 is a flow diagram showing steps used by the telecommunicationsystem of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, a telecommunication system 10 is shown toinclude a public service telephone network (PSTN) 12 and an IP network14. The services of the IP network 14 are provided by IP network ServiceProviders (ISPs) 13. These ISPs 13 are accessed by personal computer(PC) connected modems, not shown, at PSTN subscriber's business, home,hotel room, airport, for example, or by dedicated leased lines from LANs19. It should also be noted that the ISPs 13 are also connected to cablecompanies (CATV) 21 to enable direct, non-modem, connections into the IPnetwork 14 from a PC or digital telephone. Each of the ISPs 13 has aunique TCP/IP address to enable their interconnection through the IPnetwork 14. When accessing the ISP 13 with a modem, the ISP 13 makesavailable a modem in a modem pool using a “point-to-point” protocol.When accessing the ISP 13 with a direct leased line, as from a LAN 19 orcable company (CATV) 21, data packets transfer between the LAN 19, orcable company 21, and the IP network 14 directly as IP packets ofinformation. In each case, the routing through the IP network 14 is withthe TCP/IP network protocol with each point on the IP network 14 havinga TCP/IP address. It is noted that a router server 30 is coupled to theIP network 14 to convert between an E.164 telephone number and TCP/IPaddress. Thus, for example, if a cable user wishes to call a calledparty on the cable system, the calling party dials the called party'sE.164 directory number, the router server 30 converts the dialled numberto an TCP/IP number, the call is routed through the IP network 14 to theTCP/IP address of a gateway 32, which then converts the TCP/IP addressto the called party's E.164 directory telephone number. The output ofthe gateway 32 is connected to the PSTN 12.

The PSTN 12 includes a plurality of connected central offices (C.O.s) 16a, 16 b, . . . 16 n. Each one of the central offices 16 a-16 n issimilar, an exemplary one thereof, here central office 16 a being shownin detail. Thus, central office 16 a is connected to a plurality of thePSTN subscribers 18 through subscriber/central office telephone lines 20(i.e. a twisted-pair typically within two miles of the central office 16a). The PTSN subscribers 18 include business and residential subscribersto the PSTN 12. Thus, for example, if one of the residential subscriber18 may have in addition to a telephone, a personnel computer (PC)connected to the subscribers telephone line 20 through a modem, notshown. A business subscriber 18 may be connected to the central office16 a through POTS, PBX, or ISDN service, for example. The centraloffices 16 a-16 n are shown interconnected by trunks lines (i.e., units)23. One of the trunk lines 23 is connected to a gateway 32. Some of thecentral offices, such as office 16 b, are connected directly to centraloffice 16 a by a trunk and other, more remote central offices, such ascentral office 16 n, are connected indirectly to central office 18 athrough tandem switches 25, as shown. It should be understood that thePSTN 12 is here a worldwide network and interconnections among thecentral offices 16 a-16 n include satellite links or optical fiber cable(SONET), for example. Further, the interconnection may be throughvirtual circuits, as when links in the network 12 use packet switches,such as ATM switches.

Referring to exemplary central office 16 a, such office 16 a includes: aprocessor 22 coupled to a plurality of subscribers 18 through aconcentrator 27 and a subscribe line unit 24; trunk units 23 coupled toother ones of the central offices 16 b-16 n, as shown; an IP networkinterface 27 for converting between a central office protocol and anTCP/IP network protocol; a switching network 28; an administrationdatabase 30; and a features database 32, as shown. The processor 22 iscoupled to the IP network 14 through a trunk unit 29 and the IP networkinterface 27, as shown.

The switching network 28 has ports fed by the subscriber line unit 24,the trunk units 23, the trunk unit 29, and the IP network interface 27.The switching network 28 routes calls between the ports of the switchingnetwork 28 selectively in accordance with switching signals provided bythe processor 22 in accordance with the central office protocol. Theadministrative database 30 is addressable by a calling party E.164address and stores billing information and other statisticalinformation. The features database 32 stores a relationship between eachone of the PTSN subscribers 18 served by the central office 16 a andfeatures subscribed to by such one of the served PTSN subscribers 18.These features, herein collectively referred to as calling features,include, for example: call waiting, call forwarding, three-way calling,speed calling, caller ID, voice mail, and Centrex Business TelephoneGroups.

As noted in FIG. 1, the features database is addressed using the centraloffice protocol which uses an E.164 number to identify the callingparty's telephone number. Thus, for example, the PTSN subscriber 18calling from telephone number NXX-XXX1 has, in this example, subscribedto call waiting, 3-way calling, call forwarding, call hold and is amember of a centrex group.

The processor 22 includes a subscriber port ID unit 40 for identifyingthe calling subscriber's directory number (i.e., an E.164 numberprotocol). The processor 22 also includes a trunk ID unit 42 fed by thetrunk units 23 for identifying a calling party's or a called party'sE.164 directory number. The processor 22 is also fed the E.164 numberproduced by the IP network interface 27 when a call is received by asubscriber to the central office 16 a through the IP network 14. Thismay be where the PTSN subscriber 18 is on a trip and logged into an ISP13 serving central office 16 n, for example. The processor 22 includesan IP network “Flag” 31 which is set when the calling PTSN subscriber 18is accessing the central office 16 a through the IP network 14 (i.e,through the IP network interface 27).

The processor 22 detects when a calling one of the subscribers 18 servedby the central office 12 is accessing the central office 12 from eitherthe subscriber line unit 40 or the IP network interface 27. Theprocessor 22 addresses the features database 32 and the administrativedatabase 30 using the central office protocol (e.g. analog, ISDN, orPBX) to provide such calling PTSN subscriber 18 with his/her subscribedcalling features.

Referring now to FIG. 2, two scenarios are depicted: the one on the leftis when a calling party is accessing the central office 16 a through theIP network via the IP network interface 27; and the one on the leftdepicts the scenario when a calling party is accessing the centraloffice 16 a through the subscriber line unit 24 or the trunk lines 23(i.e., through the PSTN 12). Thus, when a call is placed to the centraloffice 16 a through the PSTN 12, the calling party goes “off-hook” (Step202). The central office 16 a returns “dial-tone” and identifiessubscriber's E.164 via subscriber port ID unit 40 (Step 204). Thecalling party enters the called party digits (Step 206). The centraloffice processor 22 addresses “features” and “administration” databases30, 32, respectively, with calling subscriber's E. 164 and providesprocessor 22 with calling features subscribed to by the calling party(Step 208). The central office 16 a reads the called party digits togenerate routing control signals for central office switching network 28(Step 210). The processor 22 addresses the “features” and“administration” databases 30,32 with the called party's E. 164 andprovides the processor 22 with the features subscribed to by the calledparty (Step 211). The processor 22 checks the called party's IP networkflag. (i.e., Has the IP network “flag” 31 been set ?) (Step 211). If thecalled party has logged onto the IP network, the IP network interface 27at the central office 16 a converts central office protocol into TCP/IPnetwork protocol for switching network 22 and routes call to calledparty via the IP network 14 using called party's TCP/IP IP networkaddress protocol (Step 216). If, on the other hand, the called party hasnot logged onto the ip network (i.e. the IP network “flag” 31 has notbeen set), the switching network 28 routes call to called party throughPSTN 12 using called party's E. 164 (Step 214).

Considering now the case where the central office 16 a has been accessedthrough the IP network 14. Here, the calling party logs onto the IPnetwork 14 using the local IP network Service Provider (ISP) 13 (Step218). The client software is called up in the calling party's PC (Step220). The client software includes: the central office's IP networkTCP/IP address; the subscriber's E. 164; and the subscriber's personalidentification number (PIN) (Step 220). The calling party enters calledparty digits on his/her PC (Step 222). The client software sends, viathe PC, the subscriber's E. 164 to central office via the ISP 13 usingcentral office TCP/IP IP network protocol (Step 224). The IP networkinterface 27 at the called central office 16 a converts the TCP/IP IPnetwork protocol into central office protocol and sets “IP network flag”31 to indicate to calling party has logged onto IP network 14 (Step226). At this point, the central office 16 a processes calls placed toit from the PSTN 12 or the IP network 14 in the same manner. Thus, thecentral office processor 22 addresses “features” and “administration”databases 30, 32, respectively, with calling subscriber's E. 164 andprovides processor 22 with calling features subscribed to by the callingparty (Step 208). The central office 16 a reads the called party digitsto generate routing control signals for central office switching network28. The processor 22 addresses the “features” and “administration”databases 30,32 with the called party's E. 164 and provides theprocessor 22 with the features subscribed to by the called party (Step211). The processor 22 checks the called party's IP network flag. (i.e.,Has the IP network “flag” 31 been set ?) (Step 212). If the called partyhas logged onto the IP network, the IP network interface 27 at thecentral office 16 a converts central office protocol into TCP/IP IPnetwork protocol for switching network 22 and routes call to calledparty via the IP network 14 using called party's TCP/IP IP networkaddress protocol (Step 216). If, on the other hand, the called party hasnot logged onto the IP network (i.e. the IP network “flag” 31 has notbeen set), the switching network 28 routes call to called party throughPSTN 12 using called party's E. 164 (Step 214).

It is noted that the central office 16 a, with its switching network 28,processor 22 and databases 30, 32 are, because of the IP networkinterface 27, available as an accessible adjunct to the all users of theIP network 14. Thus, a central office with the IP network interface canbe configured as a worldwide Centrex, a cable-based IP provider canaccess the central office and route telephone calls or other data tosubscribers of the PSTN or to others connected to the cable-based IPnetwork.

More particularly, referring to FIG. 3 a telecommunication system 10′ isshown where a cable-based IP network 14′ is coupled to cable modems 400and cable company central offices 16 a′-16 n′. The cable modems 400 arecoupled to Subscriber personal computers (PCs) 402 and telephones 404,as indicated. The cable-based central offices 16 a′-16 n′ are similar tothe central offices 16 a-16 n described in connection with FIG. 1 andlike elements are designated with the same numerical designation. Thus,the central offices 16 a′-16 n′ are connected to the PSTN 12 by thetrunk units 23, as indicated. The central offices 16 a′-16 n′ eachincludes a call processor 22′, trunk ID 40, administration database 30,features database 32, IP network 27 interface coupled to the cable-basedIP network 14, trunk unit 25 and switching network 28′.

With the system 10′, Subscribers connected to the cable-based IP network14′ by the modems 400 are able to subscribe to the same telephonefeatures available to subscribers of the central offices 16 (FIG. 1).Thus, referring to FIG. 4, a flow diagram shows the steps used by thetelecommunication system of FIG. 3 in enabling a subscriber to callingfeatures available by a cable company's central office of the system tohave access to such calling features when such subscriber is accessingthe central office through a cable based IP network. It is noted thatthe method does not use Steps 202, 204, or 206 described above inconnection with FIG. 2, and here the “Internet Flag” 31 is always in a“set” condition.

Referring now to FIG. 5, a telecommunication system 10″ is shown. Here,the IP network 14 is connected to the PSTN 12 through gateways 32,subscriber PCs through ISPs 13, and a router 30, as shown. Each centraloffice 16 a″-16 n″ includes a processor 22′ like that described inconnection with FIG. 3. FIG. 6 is a flow diagram showing steps used bythe telecommunication system of FIG. 5. Here, again, as with the system10′ described in connection with FIGS. 3 and 4, the “Internet Flag” 31is always in a “set” condition. Here, because all calls originate andterminate for the central offices 16 a′-16 n′ on the IP network 14,Steps 202-206 and Steps 212 and 214 (FIG. 1) are not used.

Here, each central office 16 a″-16 n″ may be a owned by a global networkcarrier and used to deliver ubiquitous telephony feature services toworldwide subscribers of the IP network 14, for example, to allsubscribers within a worldwide corporation.

Thus, the system 10″ enabling members of a common group (i.e., acompany) to have access to a common set of calling features in thefeatures database available from the central office 16 a″. The system10″ processes signals received by the central office 16 a″, for example,from the members of the common group through the IP network 14 and makessuch calling features available to the members.

Other embodiments are within the spirit and scope of the appendedclaims.

1. A telecommunication system, comprising: (a) a central office,comprising: (i) IP network interface for converting between the centraloffice protocol and a IP network, TCP/IP, protocol, the processor beingcoupled to the IP network through the IP network interface; (ii) adatabase for storing a relationship between each one of the subscribersserved by the central office and calling features subscribed to by suchone of the served subscribers; and (iii) wherein the processor addressesthe database using the central office protocol to provide such callingsubscriber with subscribed calling features when the calling subscriberis routed to a called party; and (b) a public service telephone networkcoupled to the IP network.
 2. A method for enabling members of a commongroup to have access to a common set of calling features available froma central office, comprising the steps of: processing signals receivedby the central office from the members of the common group through an IPnetwork; and making such calling features available to the members.